This invention relates to wastewater treatment and, particularly, to the removal of radioactive particulate from liquid waste streams, particularly those generated at nuclear facilities. These radioactive particulates include organics and radioactive isotopes. In addition to the nuclear industry, our invention finds application in other industries that produce wastewaters containing radioactive material. Environmental laws regulate the discharge of wastewater containing such radioactive particulates. Radioactive isotopes result from nuclear power generation, mining ore, refining ore, milling, wash-downs, fuel preparation, cooling waters, as well as from hospitals and research facilities.
The problem addressed by our invention relates to the considerable volume of wastewaters that contain the above-mentioned contaminates throughout the world and the lack of effective, safe and economical treatment system and method.
The present invention obviates these inherent problems by providing a system and method for the continuous removal of radioactive particulate, thus rendering the wastewater free of radioactive material. These waters can then be safely discharged or, in many cases, recycled, which results in additional savings and in the preservation of natural resources, the public health and the environment.
The general object of the present invention is to provide a treatment system and method for the removal of contaminate particulates from liquid waste streams, in particular radioactive particulates. Our system for the continuous removal of radioactive particulates from a liquid waste stream comprises, a feed pump for introducing a liquid waste stream containing radioactive particulates into a treatment zone at an upstream position, a chemical addition pump, a static mixer, at least one filter, a sample port connected to a charge detector for measuring the particle charge of the liquid waste stream, a series arrangement of vessels each containing media, and a controller unit responsive to the measured particle charge of the liquid waste stream and connected to the chemical addition pump.
The method of our invention comprises treating a liquid waste stream comprising radioactive particulates in an optional bed of activated carbon to form a carbon treated stream, injecting a coagulant into the carbon treated stream, mixing the coagulant and carbon treated stream to form an admixture stream, passing the admixture stream through a first filter to remove coagulated particulates, continuously monitoring the admixture stream for the presence of charged particles and automatically controlling the injection of coagulant into the carbon treated stream, introducing the admixture stream after filtration into a series of vessels containing media, passing the admixture after contact with the media through a second filter to form a substantially particulate-free stream, and disposing of the particulate-free stream.
These and other objects and advantages of the present invention will become more fully apparent from the following detailed description when read in conjunction with the accompanying drawings.